GB2317941A - Safety shut-off valve - Google Patents
Safety shut-off valve Download PDFInfo
- Publication number
- GB2317941A GB2317941A GB9620805A GB9620805A GB2317941A GB 2317941 A GB2317941 A GB 2317941A GB 9620805 A GB9620805 A GB 9620805A GB 9620805 A GB9620805 A GB 9620805A GB 2317941 A GB2317941 A GB 2317941A
- Authority
- GB
- United Kingdom
- Prior art keywords
- closure member
- valve according
- valve
- closure
- support element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K17/00—Safety valves; Equalising valves, e.g. pressure relief valves
- F16K17/36—Safety valves; Equalising valves, e.g. pressure relief valves actuated in consequence of extraneous circumstances, e.g. shock, change of position
- F16K17/38—Safety valves; Equalising valves, e.g. pressure relief valves actuated in consequence of extraneous circumstances, e.g. shock, change of position of excessive temperature
- F16K17/383—Safety valves; Equalising valves, e.g. pressure relief valves actuated in consequence of extraneous circumstances, e.g. shock, change of position of excessive temperature the valve comprising fusible, softening or meltable elements, e.g. used as link, blocking element, seal, closure plug
Abstract
A safety shut-off valve (1) comprises a housing (2), a valve seat (3) and a closure member (6). A low melting point support (16) is arranged normally to maintain the closure member (6) spaced from the valve seat (3). A spring (14) causes the closure member (6) to bear against the support element (16). When the support element melts the spring (14) urges the closure member firmly against the valve seat. The closure member is made from sheet material (preferably steel) and so has a relatively low weight. The spring may hold the closure member against the support element with a force of at least 10-30 times the weight of the closure member. The force the spring exerts on the closure member when supported by the support element is preferably no more than twice that which it exerts when the closure member bears against the valve seat.
Description
"SAFETY SH[nKFF UPLVE" The present invention relates to a safety shut-off valve for control of fluid flaw.
It relates more specifically, but not exclusively, to a shut-off valve for use in a gas supply to stop the flaw of gas if there is a potentially dangerous increase in ambient temperature.
It is important to provide a safety shut-off valve when plastics material is used in a gas meter, for example for the meter casing or an internal gas duct. If a fire or other occurrence subjects the plastics material of the meter to intense heat it is necessary for a safety valve to shut off the flaw of gas before there is any escape of gas fran a damaged meteor.
A design of safety valve currently used for this purpose camprises a solid steel ball which is normally held spaced fran a mater inlet port by a spacer pellet of low melting point alloy material. A light duty spring holds the ball aligned centrally with the speer pellet. Increase of ambient temperature to above the melting point of the alloy results in the ball dropping and sealing against a valve seat adjacent the inlet port.
Disadvantages of this design of safety valve are slawness of response due to the thermal capacity of the valve and poor reliability when mounted in a non-vtrtical attitude. It is found also that the valve ball is easily dislodged fran alignment with the spacer pellet if the meter is knocked when inverted, e.g. by dropping the meter upside dawn.
According to an aspect of the present invention a safety shut-off valve comprises a housing, a valve seat, a closure member, a low melting point support element arranged normally to maintain a space between the valve seat and closure member and spring means to cause the closure member to bear against the support element, the closure member comprising at least in part sheet type material. A suitable material is sheet steel.
The spring means may be operable also to restrain movement of the closure nEmber fran the valve seat after the law melting point support element has melted.
According to another aspect of the present invention a safety shut-off valve comprises a housing, a valve seat, a closure member, a low melting point support element arranged normally to maintain a space between the valve seat and closure member and spring means to cause the closure mater to bear against the support element, the spring means being operable also to cause the closure member to bear firmly against the valve seat after the low malting point support element has malted. Said closure member may comprise, at least in part, sheet type material, e.g. sheet steel.
The spring means preferably is operable to hold the closure member against the support element with a force which is at least fifteen (15) times, more preferably at least thirty (30) times that exerted by the weight of the closure member. The spring means my exert a force which is forty (40) or more times that exerted by the weight of the closure member.
It is further preferred that the spring means is operable to hold the closure member against the valve seat with a force which is at least ten (10) times, more preferably at least thirty (30) timas, the weight of the closure member A force of forty (40) or more times that exerted by said weight my be used.
The spring means may be a coil spring, and it may be arranged to act in carpression between the housing and closure member to urge the latter against the support element or valve seat depending on whether the ambient temperature has or has not remained below the malting point of the support element.
The spring means my be a coNpression spring of a kind which has a low stiffness. The stiffness may be selected such that the force which the spring exerts on the closure per when supported by the support element is no more than twice, and preferably less than twenty five (25) per cent greater than that which it exerts when the closure member bears against the valve seat.
A suitable low melting point alloy is one having a malting point below 100"C.
The closure member may be substantially in the form of a hollow member, e.g.
a ball, which may be fabricated from sheet metal. Alternatively it may be of part spherical or other shape. A spherical shape is preferred for ease of retrofit to replace a conventional solid steel ball. A spherical or other shape which has a substantially closed internal chamber is preferred for preventing contaminants such as liquids and solids accumulating in the closure number.
The closure member may comprise a spigot portion. The spigot portion may assist in maintaining alignment of the closure number with the support element and/or the valve seat. The spigot member may be hollow; a cavity in the spigot number my carnuolcate with an internal chamber of a spherical or other shaped portion of the closure itber.
The valve seat my be defined by the valve housing, or by the inlet port region of another component, such as a mater. The valve housing may be integral with a meter, and the subject invention provides also a fluid flaw meter which is integral with the safety shut-off valve of the invention.
An embodiment of the invention is now described, by way of exanple, with reference to the Drawings in which:
Figure 1 is a sectional view of a safety shut-off valve of the present
invention, and
Figure 2 shaws the valve of Figure 1 in association with a gas mater.
A shut-off valve 1 comprises a tubular metal housing 2 having an internal part-spherical surface 3 which defines a valve seat.
One end 4 of the housing has an external screw thread for connecting to a gas supply pipe. The other end 5 has an internal screw thread for connecting to the inlet port of a gas mater 18.
The housing contains a closure number 6 which is substantially in the form of a hollow ball having a tubular spigot extension 7.
The closure member is constructed in two parts. A lower part 8 is formed from deep drawn sheet steel and comprises a hnispherical portion 9 fran which the tubular spigot extension 7 extends centrally. The free end 10 of the spigot extension is closed by the sheet steel. An upper part 11 of the closure member also is formed fran deep drawn sheet steel. It is substantially hemispherical but has a stepped rim which locates as a forcefit with the rim of lower portion 9. Upper part 11 also has a flat central region 12 bordered by a step 13.
The step 13 provides location for one end of a compression coil spring 14.
The other end of the spring is retained by a shoulder 15 defined by an internal step in the valve housing.
Compared to a conventional solid type closure member of equivalent size and weighing approximately 80 gm, the hollow closure member 6 has a weight of approximately only 10 gm.
A support spider 17 is secured relative to the lower end 5 of the housing and supports centrally a pellet 16 of low malting point alloy, which melts at 96"C. The spider my be secured to the housing, or may be secured to a part of a mater body. The pellet 16 acts normally as a support element to hold the hemispherical portion 7 of the closure number spaced fran the valve seat 3.
When the valve is subjected to an elevated temperature above the malting point of the pellet the pellet ceases to provide support for the closure member which is then positively urged dswnwerds onto the valve seat by the force of the spring 14. The coil spring 14 has a low stiffness characteristic. In normal use, with the closure member extension spigot 7 supported by the pellet 16, the spring is arranged to exert on the closure medber a force in the order of 400 gm, which is approximately forty (40) times greater than that exerted by the weight of the closure member. This ensures that the closure member spigot is held against and maintained aligned with the pellet even if the valve is inverted. If the pellet melts,the low stiffness characteristic of the spring results, in this enodimant, in the closure member being held against the valve seat 3 with a substantially similar force, i.e. a force well in excess of the closure
If the valve is intended to be, or at risk of being, installed in an inverted manner, or horizontally or inclined, the spring is selected, for example as in the case of the aforedescribed spring, so as always to exert on the closure member a force substantially greater than that exerted by the weight of the closure member. If the pellet melts the closure member will still be held positively against the valve seat irrespective of any change in pressure, or absence of positive pressure, in the gas supply pipe.
The hollow construction of the closure member, and use of sheet material to construct it, gives a useful reduction of thermo1 capacity and iirprovement of response time in comparison with a conventional valve. The low weight allows the closure member to be fully supported by a coil spring and there is no need to provide an unduly strong spring. Softer low melting point alloy materials, e.g. having a lower melting point, my be used.
Claims (25)
1. A safety shut-off valve comprising a housing, a valve seat, a closure member, a law malting point support element arranged normally to maintain a space between the valve seat and closure member and spring means to cause the closure member to bear against the support element, the spring means being operable also to cause the closure member to bear firmly against the valve seat after the low melting point support element has melted.
2. A valve according to claim 1, wherein the closure member comprises sheet type material.
3. A valve according to claim 1 or claim 2, wherein the spring means is operable to hold the closure memhPr against the support element with a force at least fifteen times that exerted by the weight of the closure member.
4. A valve according to claim 3, wherein said force of the spring means is at least thirty times that exerted by the weight of the closure rrwS3er.
5. A valve according to any one of the preceding claims, wherein the spring means is operable to hold the closure member against the valve seat with a force at least ten times the weight of the closure member.
6. A valve according to claim 5, wherein said force of the spring means is at least thirty times the weight of the closure member.
7. A valve according to any one of the preceding claims, wherein the spring means is a coil spring.
8. A valve according to any one of the preceding claims, wherein the spring means is arranged to act in catpression between the housing and closure maner.
9. A valve according to any one of the preceding claims, wherein the spring means comprises a canpression spring.
10. A valve according to claim 9, wherein the force which the spring exerts on the closure matter when supported by the support element is no more than twice that which it exerts when the closure member bears against the valve seat.
11. A valve according to claim 10, wherein said force exerted by the spring when the closure member is supported by the support element is less than twenty five per cent greater than that which it exerts when the closure member bears against the valve seat.
12. A valve according to any one of the preceding claims, wherein the low melting point alloy has a melting point below 100"C.
13. A valve according to any one of the preceding claims, wherein the closure manner comprises sheet metal.
14. A valve according to any one of the preceding claims, wherein the closure mutter comprises a hollow member.
15. A valve according to any one of the preceding claims, wherein the closure mw3ser comprises a surface which is at least part spherical.
16. A valve according to any one of the preceding claims, wherein the closure member comprises a hollow sheet metal ball.
17. A valve according to any one of the preceding claims, wherein the closure member comprises a substantially closed internal chamber.
18. A valve according to any one of the preceding claims, wherein the closure member comprises a spigot portion.
19. A valve according to claim 18, wherein the spigot portion assists in maintaining alignment of the closure member with at least one of the support element and valve seat.
20. A valve according to claim 18 or claim 19, wherein the spigot member is hollow.
21. A valve according to any one of the preceding claims, wherein said valve seat is defined by the valve housing.
22. A valve according to claim 1 and substantially as hereinbefore described.
23. A fluid flow meter having an inlet which catprises a valve according to any one of the preceding claims.
24. A fluid flow meter according to claim 23, wherein the valve housing is integral with the meter.
25. A fluid flaw meter according to claim 23 and substantially as hereinbefore described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9620805A GB2317941A (en) | 1996-10-05 | 1996-10-05 | Safety shut-off valve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9620805A GB2317941A (en) | 1996-10-05 | 1996-10-05 | Safety shut-off valve |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9620805D0 GB9620805D0 (en) | 1996-11-20 |
| GB2317941A true GB2317941A (en) | 1998-04-08 |
Family
ID=10801000
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9620805A Withdrawn GB2317941A (en) | 1996-10-05 | 1996-10-05 | Safety shut-off valve |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2317941A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2417425A (en) * | 2004-08-25 | 2006-03-01 | Boc Group Plc | Oxygen administration apparatus with safety valve |
| GB2424259A (en) * | 2005-03-19 | 2006-09-20 | Linden Shield Ltd | Valve assemblies |
| EP2520837A1 (en) | 2011-05-05 | 2012-11-07 | Air Products and Chemicals, Inc. | Fire safety valve |
| RU2473000C1 (en) * | 2012-01-16 | 2013-01-20 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Новгородский государственный университет имени Ярослава Мудрого" | Thermal shutoff valve |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1370802A (en) * | 1972-08-23 | 1974-10-16 | Beazley R T | Fluid isolating valves |
| GB1428249A (en) * | 1972-12-20 | 1976-03-17 | Fischer Ag Georg | Thermal safety valve |
| GB1541136A (en) * | 1975-01-21 | 1979-02-21 | Inovel Sa | Ventilation opening |
| GB2004352A (en) * | 1977-09-13 | 1979-03-28 | Talbot & Co Ltd F | Automatic shut-off valve |
| US4488566A (en) * | 1983-06-22 | 1984-12-18 | The Singer Company | Thermally responsive slam shut valve assembly |
| WO1996027750A1 (en) * | 1995-03-03 | 1996-09-12 | Streif, Hans | Temperature-sensitive shut-off fitting |
-
1996
- 1996-10-05 GB GB9620805A patent/GB2317941A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1370802A (en) * | 1972-08-23 | 1974-10-16 | Beazley R T | Fluid isolating valves |
| GB1428249A (en) * | 1972-12-20 | 1976-03-17 | Fischer Ag Georg | Thermal safety valve |
| GB1541136A (en) * | 1975-01-21 | 1979-02-21 | Inovel Sa | Ventilation opening |
| GB2004352A (en) * | 1977-09-13 | 1979-03-28 | Talbot & Co Ltd F | Automatic shut-off valve |
| US4488566A (en) * | 1983-06-22 | 1984-12-18 | The Singer Company | Thermally responsive slam shut valve assembly |
| WO1996027750A1 (en) * | 1995-03-03 | 1996-09-12 | Streif, Hans | Temperature-sensitive shut-off fitting |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2417425A (en) * | 2004-08-25 | 2006-03-01 | Boc Group Plc | Oxygen administration apparatus with safety valve |
| GB2417425B (en) * | 2004-08-25 | 2006-11-22 | Boc Group Plc | Oxygen administration apparatus |
| GB2424259A (en) * | 2005-03-19 | 2006-09-20 | Linden Shield Ltd | Valve assemblies |
| EP2520837A1 (en) | 2011-05-05 | 2012-11-07 | Air Products and Chemicals, Inc. | Fire safety valve |
| RU2473000C1 (en) * | 2012-01-16 | 2013-01-20 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Новгородский государственный университет имени Ярослава Мудрого" | Thermal shutoff valve |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9620805D0 (en) | 1996-11-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |